热处理对近β锻造的多元Ti_2AlNb基合金组织和性能的影响  

Effect of Heat Treatment on Microstructure and Mechanical Properties of Near-β Forged Ti_2AlNb Based Alloy

作　　者：何永胜[1,2] 胡锐[1] 罗文忠[2] 何涛 赖运金[2] 杜玉俊[2] 刘向宏 杨劼人[1] He Yongsheng;Hu RuiI;Luo Wenzhong;He Tao;Lai Yunjin;Du Yujun;Liu Xianghong;Yang Jieren(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China;Shaanxi Province Engineering Laboratory for Aerial Material,Western Superconducting Technologies Co.,Ltd,Xi'an 710018,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]西部超导材料科技股份有限公司陕西省航空材料工程实验室,陕西西安710018

出　　处：《稀有金属材料与工程》2018年第11期3460-3467,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51601146);博士后基金项目(2017M613234)

摘　　要：以近β锻造的多元Ti_2AlNb基合金Ti-22Al-25Nb-1Mo-1V-1Zr-0.2Si(原子分数,%)为实验对象,采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和万能试验机等测试手段研究了不同热处理对近β锻造Ti2AlNb基合金组织和力学性能的影响。结果表明:经近β锻造空冷后的组织由初生α2相、针状O相和基体B2相构成。随着固溶温度的升高,合金室温、高温强度升高,塑性降低。而随着时效温度的升高,合金的强度和塑性变化规律与固溶处理的规律正好相反。分析认为,固溶处理主要影响合金中初生α_2/O相体积分数,随着固溶温度的升高,初生α_2/O相体积分数减少,使得针状O相的强化作用增强,同时造成α2相对B2晶界钉扎减弱,B2晶粒长大塑性降低。时效处理主要影响析出相形态,随着时效温度的降低,合金中析出板条厚度减小,使得细小板条强化作用增加,而有利于塑性的B2相体积分数减少,导致合金塑性降低。The new multi-compositional Ti2AlNb alloy Ti-22Al-25Nb-1Mo-1V-1Zr-0.2Si was treated by the process of near β forging and heat treatments.The effects of heat treatments on the microstructure and mechanical properties were analyzed by the scanning electron microscopy(SEM),transmission electron microscopy(TEM) and tensile test machine.The results show that the initial microstructure consists of the primary α2 phase,the needle like O phase and the matrix B2 phase.On the one hand,with the increase in solid solution temperature,the alloy strength is enhanced at room and high temperature,but the alloy ductility is reduced.On the other hand,with the increase in aging temperature,the variation of strength and ductility is completely opposite,compared to the increase in solid solution temperature.The primary alpha phase volume fraction(α2/O) is mainly influenced by the solid solution treatment for the alloy.With the increasing of the solution temperature,the volume fraction of primary α2/O alpha phase is reduced,enhancing the strengthening effect of needle like O phases.At the same time,the grain boundary pinning effect of the α2 to B2 phase is weakened,and then the growth of B2 grain decreases the plasticity.The morphology of precipitated phase is mainly affected by aging treatment.With the decrease in aging temperature,the thickness of precipitated fine O phase is decreased to enhance the strengthening effect of O phase,thus decreasing the volume fraction of B2 phase and the ductility of the alloy.

关 键 词：多元Ti2AlNb合金 近Β锻造 微观组织 力学性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]